The present invention relates to fan-forced positive pressure breathing apparatus, commonly known as Powered Air Purifying Respirators (PAPRs). In particular, the invention concerns rapid engagement mounting systems for affixing breathing components to the blower housing of the PAPR. Breathing components might include filter elements, hose attachments for supplied air, or other components required to complete a breathing circuit. Rapid engagement mounting systems are generally defined as reversible attachments that allow the deployment of a breathing component by pressure fit, sliding engagement, or rotational locking with less than one full revolution of the component.
Non-powered air purifying respirator equipment involves a breathing mask having a filtered air inlet. Air is drawn through the filter by means of the wearer""s breathing action. When the wearer draws a breath, negative pressure is created in the mask and air is drawn though the filtering element. When the wearer expels a breath, spent air leaves the mask through a valve. PAPRs are employed to continually supply positive pressure to the wearer""s mask. The filtered supplied air replenishes the internal confines of the mask and is continually ejected. To provide ease of replacement of the filter elements on non-powered respirators, bayonet type of attachments are often employed. These attachments require less than one full turn of the filter to engage the cartridge to the respirator body.
PAPRs are generally used in industrial applications where the environmental hazards are well defined and quantified. Respiratory hazards might include harmful gases, vapors, and particulate matter. To address generally known and quantified industrial hazards, a PAPR can be configured well in advance of entry into the workplace, and the amount of time a worker spends in a hazardous environment can also be well managed. In industrial settings, PAPR systems that employ multiple-turn screw type attachments for connecting the breathing components require more effort and time to properly affix.
First responders (HazMat, police, fire, and civil defense), military or other emergency response units are not afforded the opportunity to preemptively manage hazardous respiratory exposure. Depending on the nature of the exposure, the responder must quickly configure the respiratory system to adapt to the need. Exposure duration and levels are also unknown transients in the protection equation. In certain situations, the responder may not be able to extract themselves from the exposure arena and could be required to make a xe2x80x98hotxe2x80x99 change-out of the PAPR breathing components. An example of this situation might be found in a military theater where the user could be required to replenish filters while remaining in the exposed area.
The present invention relates to Powered Air Purifying Respirators (PAPRs) that incorporate breathing components adapted for rapid engagement with the blower housing of the system. In a preferred embodiment, the invention further provides for engagement detection elements that indicate the proper engagement of the breathing component to the PAPR housing. Rapid engagement breathing components combined with engagement detection elements, afford superior wearer protection in situations where a PAPR is required to be quickly configured to a respiratory hazard or when xe2x80x98hotxe2x80x99 change-outs of the breathing components are desired. The inclusion of engagement detection elements on a PAPR system provides any user with a higher level of system integrity regardless of the application.
PAPR systems of the present invention differ from known PAPRs in two basic aspects that involve both the attachment and detection system. Known PAPR systems employ screw-type attachments to affix filters to the blower housing. These screw-type attachments are multiple-turn in nature and do not lend themselves to rapid engagement of a filter. Multi-turn screw systems are also susceptible to cross threading if care is not taken with their attachment. Rapid engagement attachment systems are particularly suited to rapid configuration and deployment of PAPR systems, especially in first-responder or military situations.
Rapid engagement attachments require a minimum, if any, rotation of the breathing component by using highly pitched threads to connect the filter cartridge to the blower housing. In addition, the rapid engagement connection releasably locks the filter cartridge to the blower by using opposing detents to form a seated engagement between the blower housing and filter cartridge. This prevents the filter cartridge from accidentally disconnecting from the blower housing.
Attachment systems of known PAPRs also do not employ engagement detection elements. The only indication of proper engagement of the filter to the housing is the resistance to turning that could be misinterpreted if the filter was cross-threaded. The engagement detection system of the present invention provides a definitive indicator of attachment, both at the point of fixing and during use of the system. Engagement detection systems of the invention are especially useful in fail-safe and xe2x80x98hotxe2x80x99 change out applications, where actions of the blower motor or flow damper components can be actuated as a function of component engagement.
The engagement detection system of the invention may employ electrical, mechanical or optical contacts. As part of a circuit, an electrical or optical contact between the breathing component and the PAPR body is operably coupled to an auditory or visual signal to indicate proper seated and sealed engagement of the components. This type of arrangement could also be used, for instance, to actuate dampers to reverse air flow through the blower housing causing air to exhaust in order to enable xe2x80x98hotxe2x80x99 change-outs of the breathing component. In addition or optionally, a mechanical contact could provide an auditory or tactile indication of proper contact and could also incorporate a disengagement fail-safe to prevent the breathing component from reversing off its attachment.